Keratin is a structural fibrous protein that serves as the fundamental building block for the outer layer of the skin, and is the primary component of hair and nails. This protein is responsible for providing tensile strength, elasticity, and a protective barrier against external damage. Boosting the availability of keratin involves a two-pronged strategy: supporting the body’s internal production through nutrition and applying external products for temporary surface repair.
Nutritional Components for Keratin Production
Keratin is unique due to its high content of sulfur-containing amino acids, which are the raw materials for its rigid structure. The amino acid L-Cysteine is the key structural component, as its sulfur atoms link together to form strong disulfide bonds that confer keratin’s exceptional strength and rigidity. L-Methionine is another sulfur-containing amino acid that is considered essential because the body cannot produce it, and it acts as the precursor necessary to synthesize Cysteine.
The synthesis process relies on several cofactors to function efficiently. Biotin, a water-soluble B-vitamin, plays a role in the metabolic pathways that support keratin production. Minerals like Zinc and Iron are also required, with Zinc supporting the reproduction of keratinocytes, the cells that produce keratin, and Iron being necessary for regulating keratin expression.
Dietary Sources and Targeted Supplements
An adequate intake of high-quality protein from sources like eggs, lean meats, and fish provides the necessary amino acids, including Methionine and Cysteine. Eggs are particularly beneficial as they supply both protein and a good amount of Biotin.
Foods that provide sulfur compounds and cofactors also support the process. Onions and garlic contain N-acetylcysteine, which the body can convert into L-Cysteine, directly aiding the keratin structure. Additionally, foods like sweet potatoes and carrots provide provitamin A carotenoids, which are converted to Vitamin A, a nutrient that promotes keratin synthesis.
Targeted Supplements
Targeted supplements are often used to address potential nutritional gaps, with Biotin being one of the most common for hair and nail health. Biotin supplementation can be effective, particularly for individuals who are deficient, but evidence suggests it may have limited impact on those with already sufficient levels.
Supplements containing hydrolyzed collagen or keratin provide the body with amino acid precursors, which are easier to absorb than whole keratin molecules. However, the body must still utilize these precursors to build its own keratin, as the protein cannot be directly absorbed and incorporated into the hair or nail structure from a pill.
External Keratin Treatments and Products
Applying keratin externally offers a separate pathway for improving the appearance and feel of hair by repairing surface damage. Many shampoos, conditioners, and masks contain hydrolyzed keratin, which is keratin that has been broken down into smaller peptides and amino acids. These small fragments are water-soluble and have a low molecular weight, allowing them to temporarily fill in the damaged, porous areas of the hair shaft.
Professional Treatments
Professional salon treatments, often referred to as keratin smoothing treatments, provide a more intense and long-lasting cosmetic intervention. These treatments involve applying a liquid keratin formula combined with chemical agents, which a stylist then seals into the hair using high heat from a flat iron. The heat is necessary to temporarily alter the hair’s internal structure and bond the protein to the hair shaft, resulting in a smooth, frizz-free texture that can last for several months. Some older or less regulated formulas may contain formaldehyde or its derivatives, which can pose risks from chemical fumes and may lead to hair breakage from the intense heat application.
Protecting Hair and Nails from Keratin Loss
Maintaining the strength of existing keratin is just as important as encouraging new production. Keratin is susceptible to degradation from various environmental and physical stressors, leading to structural weaknesses and breakage.
Excessive use of high-heat styling tools can permanently damage the protein structure within the hair shaft. Chemical processes, including harsh hair dyes, bleaching, and perms, aggressively break the disulfide bonds that give keratin its rigidity. Exposure to UV radiation from the sun can also contribute to the breakdown of hair keratin.
Minimizing mechanical damage is crucial for both hair and nails. This includes avoiding rough brushing, tight hairstyles that put excessive tension on the hair, and prolonged exposure of nails to water and harsh cleaning agents. Using heat protectant sprays before styling and reducing the frequency of chemical treatments are practical steps to preserve the integrity of the keratin you already have.